1. Field of the Invention
The present invention relates to a control device for a combustion apparatus. The present invention is suitable for a control device for combustion apparatus provided with a hot water supply function.
2. Description of Related Art
Combustion apparatus as typified as a gas water heater has a control device equipped in its controlling center with a microcomputer, whereby operational control on various actuators such as a gas solenoid valve for switching supply/stop of fuel gas, a proportional valve for adjusting fuel gas supply, a fan motor for adjusting combustion air blow.
Thus, if and when the microcomputer runs out of control, fuel gas supply or air blow goes out of control, resulting in excessive combustion or accidental extinction. Further, that might cause a fan out of control, resulting in deterioration of a combustion state due to disproportion of air-fuel ratio. Therefore, a means for dealing with such a problem is disclosed in a patent document 1.
A control device disclosed in the patent document 1 incorporates two microcomputers and prevents the microcomputers from running out of control by monitoring their operations each other by communication between the microcomputers.
Patent documents 2 and 3 also disclose inventions whereby a plurality of computers monitor each other, though not relating to a combustion apparatus.    Patent Document 1: JP 2002-318003A    Patent Document 2: JP 02-28735A    Patent Document 3: JP 02-230458A